1. Field of the Invention
The apparatus of the present invention relates to valves. More particularly, the present invention relates to a horizontal seal positioned in a valve body so as to reduce or eliminate emissions from various ball, plug, or butterfly valves, which normally rotate 90.degree. between full open or fully closed to allow or stop the flow of the fluid in the line.
2. General Background
Due to the hazards that are being addressed in today environment, especially in the area of plant or inadvertent gaseous emissions from plants or the like, there is increasing awareness which is devoted to assuring that greater caution is undertaken in the construction of plants and the lines in plants which carry hazardous material, in order to prevent pollution problems which plague the chemical industry. One particular type of hazard is through inadvertent atmospheric emissions, which the chemical industry is attempting to reduce pollutants from the air at the source of the emission i.e., the chemical plant itself. It has been found that most fugitive emissions from chemical plants generally originate from leaks in the lines, such as leaking flanges, pump seals, or packing that are in valves. In the area of leaks in pump seals, these are corrected through more efficient seal designs.
In general, leaks in flanges are controlled by utilizing additional welded pipe rather than having to join segments of pipe in flanged joints. In the case of vapor leaks, that may escape through valves, this type of leak may be the most difficult to control, in view of the fact that in most cases, the leak has occurred in the packing gland of the valve prior to the need for adjustment being noted. For purposes of explanation, the packing gland is usually a material that is contained within the valve body, and would usually surround the valve stem and would be compressed between the body of the valve and the stem and would serve as a seal for fluids that may seep around the valve stem, and theoretically would prevent the leak from proceeding past the packing material. However, in view of the fact that the packing material often times is inadequate, and only forms a vertical seal, and may not be effecting a complete fluid tight seal, the fluid or gas is able to leak past the packing material around the stem space and out of the valve into the atmosphere.
It would therefore be a desirable feature in what are termed "90.degree. valves" such as ball, plug or butterfly valves, to incorporate a simple, inexpensive valve seal that would seal horizontally in order to reduce or totally eliminate fugitive emissions. Such a seal in combination with a 90.degree. valve is disclosed in the present invention.
The present inventor is the named inventor in U.S. Pat. No. 4,671,314, entitled "Flow Line Sampler Valve Apparatus", which discloses a stationary sealing wafer which served as a seal against the flow of fluids out of the valve other than through the valve flow line. The wafer was constructed preferably of Teflon material for carrying out the sealing function.